Initial commit: Laravel scaffold + Common Crawl site indexing

Adds Site/SitePage models and the crawlindex:fetch command, which pulls
CDX index records from Common Crawl and optionally enriches them with
page title/description/keywords/body text extracted from the WARC
archive. CDX/WARC access and the site/page upsert logic live in
CommonCrawlIndexService and WarcRecordFetcher.

app/Models/SitePage.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class SitePage extends Model
+{
+    protected $fillable = [
+        'site_id',
+        'urlkey',
+        'url',
+        'timestamp',
+        'mime',
+        'mime_detected',
+        'status',
+        'digest',
+        'length',
+        'offset',
+        'filename',
+        'languages',
+        'charset',
+        'redirect',
+        'title',
+        'description',
+        'keywords',
+        'content',
+        'raw',
+        'record_hash',
+    ];
+
+    protected $casts = [
+        'raw' => 'array',
+        'status' => 'integer',
+        'length' => 'integer',
+        'offset' => 'integer',
+    ];
+
+    public function site(): BelongsTo
+    {
+        return $this->belongsTo(Site::class);
+    }
+}